A sensor for detecting state quantities (gas concentration, temperature, etc.) of a measurement target has been known. For example, a sensor includes: a sensor element having a detection portion; a metal shell that holds the sensor element via an element holding member; and an element protector that is formed in a shape covering the sensor element and is fixed to the metal shell (Japanese Patent Application Laid-Open (kokai) No. 2003-185620).
As an example of such a sensor, a gas sensor for detecting a specific gas contained in a measurement target gas has been known. A gas sensor is used for, for example, detecting a specific gas (oxygen, NOx, or the like) contained in an exhaust gas from an internal combustion engine.
Regarding a sensor applied to use in which the temperature of a measurement target is high, improvement of heat resistance can be achieved by, for example, forming an element protector, which is a member directly contacting the measurement target, of a material having excellent heat resistance.